Burglar-alarm for glass doors



Unirse Sterns JAMES B. GILL, OF SAN FRANCISCO, CALIFORNIA.

BURGLAR-ALARIVI FOR GLASS DOORS.

SPECIFICATION forming part of Letters Patent No. 535,100, dated March 5,1 895. Application tiled February 27, 1893.A Serial No. 463,800. (Nomodel.)

To all whom t may concern.-

Be it known that I, JAMES B. GILL, a citi- Zen of the United States,residing in the city and county of San Francisco, State of California,have invented a new and useful Burglar- Alarm for Glass Doors, Windows,&c.,of which the following is a specification.

The object of my invention is to provide a means for immediateannouncement of attempted burglaries through glass-doors, plateglass andother windows, sky-lights, transoms, duc. I attain this object by themeans illustrated in the accompanying drawings which form part of thisspecification, and in which- Figure l represents an inside view of alarge plate-glass window embodying my invention and showing a thin stripof metal around the border of the plate with connecting Wires and parts.Fig. 2 is a view in perspective of a pad by which the Wires are securedto the border.

A represents a thin narrow strip or film of silver or other conductor ofelectricity connected to the face of the glass by some adhesivesubstance which extends all around the glass near the frame in anunbroken line save at one corner preferably the upper corner.

To e'ech end'of the film or strip of conducting metal I connect a pad B,B, (best shown in Fig. 2) which is composed of a narrow strip ofblotting paper interiorly lined With a film or strip of the samesubstance as the film or strip around the glass pane is composed of, andof the same width as that of the blotting pad. The pads are held inposition and in contact with the film by means of springs B fastenedtothe Window-frame. These pads B,B, are connected by means of the .wiresC, CX with a closed battery circuit of a burglaralarm appliance (notshown) which causes an alarm to sound when the circuit is broken wouldnaturally congregate at such a place as a store front at the sound ofbroken glass. In such an attempt to gain entrance to a building bycracking or breakingthe pane of glass provided with the safeguard abovedescribed it is quite evident that in breaking the glass the lm willalso be broken or ruptured and the electric circuit connecting the wiresWith the burglar alarm will be broken at once.

The film may be of gold, silverquicksilver or other conducting substanceand may be made to adhere to the glass in straight border lines as shownin the drawings or be applied in curved lines forming ornamentalborders, but under such conditions as that, the border should becontinuous and unbroken save and except at one corner as above setforth.

Having thus described my invention, What I claim, and desire to secureby Letters Patent, is-

In a burglar alarm a thin strip or film of metal applied tothe innerface of glass-doors, windows, dac., the continuity of Which is brokenand the ends provided With conductive pads composed of -a thin strip ofconductive metal inclosed by bibulous paper, connecting with the wiresof a battery, as described.

In testimony that I claim the foregoing I have hereunto set my hand andseal.

JAMES B. GILL. [Ls]

